Inclosed-arc lamp.



PATENTED AUG. 2, 1904:.

0. N. WISWBLL. INGLOSED ARG LAMP.

APPLICATION FILED JULY 24. 1902. RENLWLD JUNE 17.1904.

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JCHSC UNITED STATES Patented August 2, 1904.

PATENT OEEICE.r

OZRO N. WISWELL, OF SNOQUALMIE FALLS, WASHINGTON, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

lNCLOSED-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 766,788, dated August 2, 1904.

Original application iiled May 4:, 1899, Serial No. 715 ,507. Divided and this application filed July 24, 1902. Renewed June 17, 19011. Serial No. 212,971. (No model.)

To rl/Z/ whom, it muy concern:

Beitknown that I, OZEo N. WrswELL, a citi- Zen of the United States, residing at Snoqualmie Falls,in the county of King, State of VVash- 5 ington, have invented certain new and usefulImprovements in Inclosed-ArcLamps, of which the following is a' specification.

This application is a division of my pending application, Serial No. 715,507, filed May 4e,

With electric-arc lamps having a small inclosing chamber around the are it is customary to provide a cover for the inclosure, which is designed to exclude as much oxygen from the I5 are as possible. This is done in order to prolong the life of the carbons.

In the practical construction of are-lamps of the inclosed type it has been impracticable to make a lit between the carbon and the cap 2O and between the cap and the inclosure which is good enough to exclude all of the oxygen from the inclosure after the lamp has started into operation, although such results are obtained as will greatly increase the carbon life.

This failure is partly due to inaccuracies in the carbons and partly to inaccuracies in the cap and inclosure. In the ordinary burning of the lamp the upper carbon pumps up and down more or less and by its action either expels a certain amount of inert gas from the inclosure or sucks into the inclosure a certain amount of oxygen. So long as a body of carbon-gas is constantly maintained in the inclesure the carbon life is greatly prolonged, but

as soon as oxygen is admitted the carbon life correspondingly decreases.

I have discovered that if a suitable chamber is provided into which the inert gas is forced instead of into the surrounding atmosphere the carbon life can be materially increased. By this construction when the distance between the carbons is decreased from any cause the amount of inert gas which is displaced by the moving carbon or carbone is forced into the chamber and remains until the carbons are again separated, when it is returned to the iuclosure, due to the pumping action of the moving carbon or carbons. Of course some gas may escape during the time that this action takes place, but the main body of gas acts in the manner described. The chamber may be of any desired character, either straight or irregular; but preferably it should be of greaterl capacity than would suflice to contain the displaced gas or combination of gases. When the chamber is of the proper size, no appreciable amount of oxygen will be admitted to the inclosure, even though the carbons move over their entire range. In other words, a chamber of suitable capacity is provided into which the gas enters or is withdrawn, the extent of movement of the carbon in no way affecting the principle of operation.

I do not wish to be understood as limiting myself to the use of a chamber the capacity of which is greater than that necessary to receive the gas displaced by the moving carbon or carbons, since excellent results can be obtained if the chamber is more limited in capacity.

In the accompanying drawings, which illustrate an embodiment of my invention, Figure 1 shows a gas-cap in cross-section with a simple form of gas-chamber. Fig. 2is a side elevation of a gas-cap. Fig. 3 is a plan view of the same with the cover removed. Fig. ft is a cross-section of the cap on line 4 4 of Fig. 3. Fig. 5 is a plan view of a slightlymodified cap. Fig. 6 is a cross-section of the same, and Fig. 7 is another modiiied form.

Referring' to Fig. 1, A represents an arcinelosing cylinder of any desired construction, and mounted on the top thereof is a gas-cap B. The cap is provided with a central opening to permit the passage of the upper carbon C. The carbon and opening are so arranged that the carbon may move freely in avertical direc tion. Surrounding the central opening and concentric therewith are chambers l) and D', in which whirls of gas or air are created when the carbon C moves up and down and prevent the free exchange of gas and air in the inclosure. Surrounding the outside of the cap is a deep groove E, forming a chamber which acts to prevent the free exit of gas from the cylinder or the entrance of oxygen.

Mounted in the cap and communicating with the chamber D is a tube F, into which the inert gas from the inclosure passes whenthe carbons are made to approach and from which a supply of inert gas is received when the carbons separate. For convenience I have shown the tube bent downward like an inverted U, but any other form may be adopted, if desired. Assuming that the carbons C and C are half-inch carbons and that the normal separation is from ahalf to iive-eighths of an inch, then the capacity of thel auxiliary gas chamber or tube F should be great enough to receive all of the gas forced out of the inclosure A, with something to spare when the carbons come together. For example, the dotted line f indicates roughly the point to which the inert gas would be forced if the carbons C and C were made to strike.

The auxiliary chamber should be so arranged that it offers verylittle resistance to the passage of the gas from the inclosure. In the present instance the tube F communicates with the concentric chamber D, and therefore it would offer slightly more resistance to the passage of the gas, or a single chamber could be substituted for those shown and the tube connected therewith, or the tube could enter the inclosure directly, as shown in Fig. 7 Instead of utilizing a tube, as shown, when the cap is held stationary and the inclosure A forced up against it the side tubes which support the yoke and lower-carbon holder may be employed and asuitable connection provided between the inclosure and the side tube or tubes. Regarding the action of this auxiliary chamber, the chambers D and Dl and the chamber formed by the groove E must not be considered as a part thereof, for they act to check the passage of gas and air, whereas the auxiliary chamber aims to present a comparatively free receptacle for the gas. In the same way that the inert gas is prevented from escaping when the carbons approach so the air is prevented from entering the inclosure when the carbons separate, for the action of the carbons separating will suck or pump back the gas previously expelled intov the auxiliary chamber.

Referring to Figs. 2, 3, and 4, I have shown a slight modification of the cap in which the auxiliary chamber F is made in the form of a spiral and lies in a horizontal plane. This arrangement is better than the one previously described, since the gas has no tendency to move when the gas in one portion of the chamber is slightly heavier than that in another portion. As before, the cap is provided with a central carbon-opening and two concentric chambers D and D', surrounding the opening, to check the free entrance of air and the exit of gas around the carbon. In additionto these chambers is a third and large chamber D2, located at the bottom, where the gascan enter with comparative freedom. This chamber communicates by a vertical hole D3 with the spiral auxiliary chamber F. The chamber F is formed by a spiral groove on the top of the cap and a cover H, which fits over the groove and is secured in place by screws. The action of this cap is the same as the one shown in Fig. l, except that the gases have no self-moving tendency due to difference in weight. This cap is more desirable from a commercial point of view, since it occupies less space, and where the tendency is toward short lamps, as it is at the present day, this is an important item.

In Figs. 5 and 6 I have shown a slight modificationof the cap previously described. The essential difference lies in the fact that the auxiliary chamber F is not made -in the form of a spiral, but consists of two communicating chambers F and F. The chambers, as shown, are concentric and are formed by grooving the top of the cap and securing a cover to the cap by screws. For convenience I have spoken of the chambers F and F; but these constitute, in effect, a single chamber.' The object in placing' the opening F2 opposite the opening F3, which communicates with the atmosphere, is to provide a longer path for the gas. There is a slight difference, however, in the construction of the auxiliary chamber from those previously described. In all the previous instances the gas and air have had but a single path to follow, whereas they now have two paths in multiple with each other, as is clearly shown by the arrows.

In placing my attachment on electric-arc lamps it is unnecessary to make special provisions for rendering the inclosure air-tight. So long as the resistance of the auxiliary chamber to the passage of gas is low the gas will enter the chamber in preference to taking the high-resistance leaks.

It will be seen that in all the types of construction employed the gaseous arc products are provided with a long and comparatively easy path of discharge and which the entering air must traverse before reaching the inclosure, and as a result the pumping action of the inclosed gases, due to the feeding of the carbons as well as to the fluctuations in the arc, will find relief through this easy path in preference to the other path, including the narrow opening around the electrode.

VVhatI claim as new, and desire to secure by Letters Patent ofl the United States, is-

l. In a cap for inclosed-arc lamps, the combination of a plate having a carbon-opening and arranged to engage with an end of the globe, and a chamber communicating with the carbon-opening at one point and with the atmosphere at another into which the gas from the inclosure is free to enter and withdraw as the carbons move with respect to each other.

i2. In a gas-cap, the combination of a plate having a carbon-opening and arranged to IDC IIO

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cover one end of an are-inelosing globe, a groove formed in the top of the plate, and a cover whereby the groove is formed into a Chamber.

3. ln a gas-cap, the Combination of a plate having a carbon-opening and arranged to eover one end oi' an areinelosing globe, a groove formed in the top of the plate, and Communicating with the Carbon-opening at one end and with the atmosphere at the other, and a cover for the groove.

4. In a gas-cap for inelosed-are lamps, the combination of a plate having a earbon-open ing, and a divided chamber formed in the cap communicating with the carbon-opening at I5 one point and with the atmosphere at another.

5. In a gas-eap for inelosed-are lamps, a hollow metal easing, adapted to rest loosely on the top of the globe and having a central opening' for the movable carbon and means 2O for equalizing the changes of pressure in the globe through a body of gas in said easing.

1n Witness whereof I have hereunto set my hand this 10th day oi' J uly, 1909.

@ZBO N. WlSl/VELL.

Witnesses:

G. W. Nomimor, M. A. JANICKE. 

